Nationalist passions may be running wild following the annexation of Crimea, but a senior Russian diplomat seems to have found an alternative way to end the crisis: Americans should do some yoga.

Deputy foreign minister Sergei Ryabkov claimed Americans have become so "fixated" on Russia's actions, they should spend more time outdoors, watching TV or doing some yoga to help them relax.

"What can one advise our U.S. colleagues to do?" he told the Interfax news agency. "Spend more time in the open, practice yoga, stick to food-combining diets, maybe watch some comedy sketch shows on TV."

The outspoken diplomat said Washington should respect "the free will of the people of Crimea" and acknowledge the "train has left" and throwing "childish tantrums" won't help ease tensions or reverse Russia's annexation of Black Sea peninsula.

Crimeans voted to leave Ukraine for the Russian Federation on 16 March following a controversial referendum condemned as illegal by Kiev and the West.

Prime Minister David Cameron dismissed the referendum as a "sham" echoing remarks made by President Barack Obama, who claimed "a sloppily organised (referendum) over the course of two weeks" would not be considered "a valid process".

In his European tour, Mr Obama said Russia was a "regional power" bullying neighbours out of weakness, not strength, and called on President Vladimir Putin to de-escalate tensions and change course.

The US and the European Union have imposed economic sanctions on wealthy Russian businessmen and individuals with close links to President Vladimir Putin, while also threatening to launch wider sanctions on the Russian economy if Moscow steps further into Ukraine.

The world leaders of the G-7, including the US, UK, France, Germany, Italy, Canada and Japan, have also cancelled a planned G-8 meeting in the Russian city of Sochi in response to the Ukrainian crisis. They will now meet in Brussels in June in an effort to isolate Mr Putin from international discussions.